Mitsubishi Electric SEZ-M-DA Series, Service Manual

Page: 105 / 130

105
MXZ-3F, 4F
No. Symptom
Indication
Abnormal point / Con-
dition
Condition Remedy
LED1(Red) LED2(Yellow)
1 Outdoor
unit does
not operate.
Lit Once LEV and drain pump
The indoor unit detects an abnormality in the LEV
and drain pump.
• Refer to 12-6. "Check of LEV".
• Check the drain pump of the indoor unit.
2
Lit Twice
Outdoor power
system
Overcurrent protection cut-out operates 3 consecu-
tive times within 1 minute after the compressor
gets started, or converter protection cut-out or bus-
bar voltage protection cut-out operates 3 consecu-
tive times within 3 minutes after startup.
• Check the connection of the compressor connect-
ing wire.
• Refer to 12-6. "How to check inverter/compres-
sor".
• Check the stop valve.
3
Lit 3 times
Discharge temperature
thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 10 minutes of compressor startup.
• Refer to 12-6. "Check of outdoor thermistors".
4
Lit 4 times
Fin temperature
thermistor
A short or open circuit is detected in the thermistor
during operation.
• Refer to 12-6. "Check of outdoor thermistors".
P. C. board tempera-
ture thermistor
• Replace the outdoor control P.C. board.
5
Lit 5 times
Ambient temperature
thermistor
A short or open circuit is detected in the thermistor
during operation.
• Refer to 12-6. "Check of outdoor thermistors".
Outdoor heat ex-
changer temperature
thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 5 minutes (in cooling) and 10 minutes
(in heating) of compressor startup.
Defrost thermistor
A short circuit is detected in the thermistor during
operation, or an open circuit is detected in the ther-
mistor after 5 minutes of compressor startup.
6
Lit 6 times
Zero cross detecting
circuit (Outdoor control
P.C. board)
Zero cross signal cannot be detected. • Replace the outdoor control P.C. board.
7
Lit 7 times Outdoor control system The nonvolatile memory data cannot be read
properly.
• Replace the outdoor control P.C. board.
8
Lit 8 times Current sensor
Current sensor protection cut-out operates 2 con-
secutive times.
• Replace the outdoor power P.C. board.
9
Lit 11 times
Communication error
between P.C. boards
The communication protection cut-out between
boards operates 2 consecutive times.
• Check the connecting wire between outdoor con-
trol P.C. board and outdoor power P.C. board.
M-NET communication
error
M-NET adapter P.C. board detects an abnormality
in the communication error.
• Check the connecting wire between M-NET
adapter P.C. board and outdoor control P.C.
board, or terminal block.
10
Lit 12 times
Zero cross detecting
circuit (Outdoor power
P.C. board)
The protection cut-out of the zero cross detecting
circuit operates 10 consecutive times.
• Replace the outdoor power P.C. board.
11
Lit 13 times Current sensor
A short or open circuit is detected in the input cur-
rent detection circuit during operation.
• Replace the outdoor power P.C. board.
12
Lit 14 times Voltage sensor
A short or open circuit is detected in the input volt-
age detection circuit during operation.
• Replace the outdoor power P.C. board.
13 Lit 15 times Relay operation No relay operation is detected during operation. • Replace the outdoor power P.C. board.
14
Lit 18 times
Detection of refrigerant
(Indoor unit)
1. Refrigerant leaks from the piping or the
heat exchanger in the indoor unit.
2. The following items are used around the
indoor unit.
• Spray (LP gas including Freon, and whose
main ingredient is propane and butane)
• Aerosol insecticide (including ethanol)
• Air spray painting (including dichlorometh-
ane)
• Charcoal (charcoal fire)
• Chemicals (such as ethanol)
• Turn off the power after the indoor unit fin -
ishes its fan operation.
(The fan operation continues for 3 hours.)
• Check the indoor unit to detect the part
where refrigerant leaks.
• Repair the part where refrigerant leaks.
• Turn on the power again.
• Replace the refrigerant sensor if the problem
is not fixed.
15
Lit 19 times
Abnormality of refriger-
ant leakage sensor
(Indoor unit)
The refrigerant sensor mounted on the indoor
unit does not work.
The refrigerant sensor is not connected prop-
erly or the wire is broken.
• Connect the connector of the refrigerant sen-
sor properly.
• Replace the refrigerant sensor.
16
Lit 20 times
Incompatible unit com-
bination error
The indoor unit which is not compatible with
the outdoor unit is connected.
• Replace the indoor unit with the one which is
compatible with the outdoor unit.
17 'Outdoor unit
stops and
restarts
3 minutes
later' is
repeated.
Twice Not lit
IPM protection
Overcurrent is detected after 30 seconds of com-
pressor startup.
• Reconnect compressor connector.
• Refer to 12-6. "How to check inverter/
compressor".
• Check the stop valve.
• Check the power module (PAM module).
Lock protection
Overcurrent is detected within 30 seconds of com-
pressor startup.
18
3 times Not lit
Discharge temperature
protection
The discharge temperature exceeds 115°C during
operation.
Compressor can restart if discharge temperature
thermistor reads 80°C or less 3 minutes later.
• Check the amount of gas and refrigerant circuit.
• Refer to 12-6. "Check of LEV".
19
4 times Not lit
Fin temperature
protection
The fin temperature exceeds during operation.
•Check refrigerant circuit and refrigerant amount.
•Refer to 12-6. "Check of outdoor fan motor".
P.C. board temperature
protection
The P.C. board temperature exceeds during opera-
tion.
20
5 times Not lit
High pressure
protection
High pressure is detected with the high pressure
switch (HPS) during operation.
• Check around of gas and the refrigerant circuit.
• Check the stop valve.
The outdoor heat exchanger temperature exceeds
70°C during cooling or the indoor gas pipe tem-
perature exceeds 70°C during heating.
OBH790D